Question: If $x \veebar y = 2x-4y$ and $x \star y = x(y-6)$, find $-6 \star (-4 \veebar -4)$.
Answer: First, find $-4 \veebar -4$ $ -4 \veebar -4 = (2)(-4)-(4)(-4)$ $ \hphantom{-4 \veebar -4} = 8$ Now, find $-6 \star 8$ $ -6 \star 8 = -6(8-6)$ $ \hphantom{-6 \star 8} = -12$.